Properties of matter Questions and Answers

at e f of A cubical block of wood of edge 3 cm floats in water The lower surface of the cube just touches the free end of a vertical spring fixed at the bottom of the pot see figure 7 111 Find the maximum weight that can be put on the block without wetting it Density of wood 800 kg m and spring constant of the spring 50 N m Take g 10 m s ellllllllll

The freezing point of pure benzene is 5 40 C and that of solution containing 2 0 gm of solute per 100 gm of benzene is 4 40 C Calculate the molecular of solute Molal depression constant is 5 C m O 10 O 1000 O 100 O 72 2 F

vertical wires 1 2 ane 3 are a rod of mass Min as the figure The wires are of equal length and equal cross sectional area It is given that Y The wires 1 and 3 are attached at the extreme ends of the rod Choose the correct option s a T 27 b 27 7 12 M c T T

Three identical balls of rubber aluminum and steel are dropped from the same height on a horizontal rigid surface If Vrubber VA1 and V steel are their speeds just after the collision then VAI 1 Vrubber 2 Vrubber VA1 V steel Vsteel 3 Vrubber Val Vsteel 4 Vrubber Vai V steel 1 23 2 21 1 1 A 3 53 1 4 5

A crystal has a coefficient of expansion 13 10 7 in one direction and 231 x 10 7 in every direction at right angles to it Then the cubical coefficient of expansion is a 462 10 7 c 475 x 10 7 b d 244 10 7 257 10 7

A soap film is formed on a vertical equilateral triangular frame ABC Side BC can move vertically always remaining horizontal If m is the mass of rod BC and T is surface tension of soap film Mark the correct statement s LEAT B C The length of BC in equilibrium is The length of BC in equilibrium is mg 2T mg T B 3m The time period of small oscillations about the equilibrium position is T The time period of small oscillations about the equilibrium position is m 3T

A perfect reversed heat engine is used for making ice at 5 C from water available at 25 C The temperature of freezing mixture is 10 C Calculate quantity of ice formed per kWhr For ice specific heat is 2 1 kJ KgK and latent heat is 335 kJ Kg

26 If p is the density of the material of a wire and othe breaking stress The greatest length of the wire that can hang freely without breaking is 20 pg a 27 If 1 b P og c Pg 20 d a pg

A 0 70 kg metal dish contains 1 kg of water at 20 C A 0 5 kg iron bar at 120 C is dropped into the water and the final temperature is 24 9 C What is the material of the dish Write your answer in CAPITAL LETTERS Ciron 11 koal kg C Cuater 1 koal kg C

2 Draw a complete shearing force and a bending moment diagram for the for the beam shown in the figure Show detailed calculations Use the last two digits of your ID number for the missing force F kN F KN 2 m B 10 kN m 10 m C

A brass wire of length 4 5m with cross section area of 3x105 m and a copper wire of length 5 0m with corss section area 4x105 m are stretched by the same load The same elongation is produced in both the wires Find the ratio of youngs modulus of brass and copper

44 A glass capillary of length 1 and inside radius r r l is submerged vertically into water The upper end of the capillary is sealed The atmospheric pressure is Po To what length h has the capillary to be submerged to make the water levels inside and outside the capillary coincide Assume that temperature of air in the capillary remains constant given surface tension of water T angle of contact between glass water interface 0 a Por b nor c 1 d

24 X 10 EX max 2 The work function of caesium metal is 2 14 eV When light of frequency 6 x 10 4 Hz is incide on the metal surface photoemission of electrons occurs What is the a maximum kinetic energy of the emitted electrons b stopping potential and c maximum speed of the emitted photoelectrons

Q 16 The axial load of 56 kN is applied to a bar of 36 mm diameter and 1 m length The extension of the bar is measured to be 0 265 mm whereas the reduction in diameter is 0 003 mm calculate the Poisson s ratio and the values of the three moduli Ans 0 314 E 207 6 GPa G 79 GPa K 186 GPa

A copper wire of cross section A is under a tension T It Young s modulus is Yand Poisson s ratio o The decrease in cross section of wire will be 16 17 OT GT 2Y 20T Y TY

Assuming Newton s law of cooling to be valid The temperature of body changes from 60 C to 40 C in 7 minutes Temperature of surroundings being 10 C its temperature after next 7 minutes is A 7 C C 21 C B 14 C D 28 C

us Pre Medical Physics 9 A glass vessel of volume 100 cm is filled with mercury and is heated from 25 C to 75 C What volur of mercury will overflow Coefficient of linear expansion of glass 1 8 x 106 C and coefficient of volu expansion of mercury is 1 8 x 10 4 C

The coefficient of volume expansion for benzene is 2 x 10 K and its bulk modulus of elasticity is 104 Pa What pressure in Pa must be applied to it such that olume of benzene remains unchanged when heated by 0 1 C

A uniform steel bar Young s modulus 200 GPa density 7 8 gm cc of total length 40 m hangs vertically The ratio of elongation of top 10 m to that of top 20 m of the bar OFFICE COPY D 7 12 would be A 1 2 C 5 8

1 Consider a head on collision between two cars One is initially at rest and the other moves toward it After the collision they stick together Sketch a position vs time graph for each car starting with time before the collision and ending a short time afterward

100 Two circular shafts of same material same length L and same outside diameter D are subjected to torques so that they develop same maximum shear stress The first shaft is solid while the second one is hollow with inner diameter D 2 The ratio of total strain energy absorbed by the first shaft to that by the second shaft is A C 4 15 16 B 7 1 D D

A cube of side 40 cm has its upper face displaced by 0 1 mm by a tangential force of 8 kN The shearing modulus of cube is 1 2 x 10 N m 2 4 x 10 N m 3 2 108 Nm 2 4 4 108 N m 2

A container has two immiscible liquids of densities p and p2 P1 A capillary tube of radius ris inserted in the liquid so that its bottom reaches upto the denser liquid The denser liquid rises in the capillary and attains a heighth from the interface of the liquids which is equal to the column length of the lighter liquid Assuming angle of contact to be zero the surface tension of heavier liquid is h Answer A B C Pi P2 Your Attempt 2 gh Pergh 2 P2 P1 gh Correct answer

Fir 1 8 x 10 5 N s m and its density is 1 2 kg m Force of buoyancy due to air is neglected An air bubble of radius 1 mm is allowed to rise through a long cylindrical column of a viscous liquid of ra 5 cm and travels at a steady rate of 2 1 cm per second If the density of the liquid is 1 47 g cc find its visc Assume g 980 cm s and neglect the density of air illan tubes connected in series Their lengths are and 20 and radii r tubes are in the ratio

A rubber cord catapult has cross sectional area 25 mm and initial length of rubber cord is 10 cm It is stretched to 5 cm and then released to project a missile of mass 5gm Taking Yrubber 5 108 N m velocity of projected missile is 1 20 ms 21 F 2 100 ms 1 o 1

Bone has a Young s modulus of about 18 x 10 Pa and can withstand compression stresses up to 160 x 106 Pa before breaking If your forearm is 0 4 m long by how much does this bone get compressed when it breaks O 1 2 mm 3 6 mm O 7 6 mm O 5 4 mm O 0 5 mm 4 2 mm

A wire of length L and cross section area A suspended at one of its end from a ceiling density and Young s modulus of material are d ar Y respectively then its elastic potential energy du to its weight is 1 3 d g AL 2Y d g AL 2 4 d g AL 6Y d g AL 3Y

When a large bubble rises from the bottom of a lake to the surface its radius is doubled The atmospheric pressure is column of water of heigh he depth of the to that of a PRATEEK Vagere H PHYSICS HOLICK lake is a 8H 1997 AIIMS

The rubber cord of a catapult has cross section area 1 mm and a total unstretched length 10 cm It is stretched to 12 cm and then released to project a partical of mass 5 g Calculate the velocity of projection Y for rubber is 5 x 108 N m 1 5 ms 2 10 ms 3 20 ms 4 40 ms

Addition of Water to a Salt Solution Pure water is added drop by drop to a vessel of volume V filled with a salt solution of specific gravity po which is allowed to overflow due to addition of water Find specific gravity of solution when a volume V of water is added Assume uniform density of solution just after adding each drop of water 0

Water is filled up to a height h in a beaker of radius R as shown in the figure The density of water is p the surface tension of water is T and the atmospheric pressure is po Consider a vertical section ABCD of the water column through a diameter of the beaker The force on water on one side of this section by water on the other side of this section has magnitude A 2 R B C h

A rigid rod AB of mass M and length is suspended horizontally from two vertical wires having same length and same area of cross section When a mass m is placed at a distance xM m 2M ym Y Y horizontal If the ratio of Young modulus of two wires Y m R is then find the value of x y from end B rod rem

The presence of flaws such as microscopic cracks and cavities will result in O lower compressive strength of ductile materials compared to their tensile strength O lower compressive strength of brittle materials compared to their tensile strength O lower tensile strength of brittle materials compared to their compressive strength O it has no significant effect

Two conductors a are made of the same material and have the same length Conductor A is a solid wire of diameter 1 1 mm Conductor B is a hollow tube of outer diameter 2 0 mm and inner diameter 1 2 mm The ratio of RA R is O O O O O O 0 47 O 2 12 1 O 3 31 O 3 33

hen a concentrated load is applied directly on a body it creates stress whose distribution is uniform except in the immediate vicinity of the point of application of the load This is known O Poisson s ratio O Dilatation Hooke s law Saint Venant s principle

48 A stream of liquid set at an angle 0 is directed against a plane surface figure The liquid after hitting the surface spreads over it Find the pressure on the surface The density of the liquid is p and its velocity is v a pv cos 0 1 c Pv cos 0 A 0 b pv cos 0 d pv cos 0

17 When at rest a liquid stands at the same level in the tubes shown in figure But as indicated a height difference h occurs when the system is given an acceleration a towards the right Here h is equal to aL a b gl h L a c GL gL d 20 a L Ar

13 When a weight of 10 kg is suspended from a copper wire of length 3 m and diameter 0 4 mm its length increases by 2 4 cm If the diameter of the wire is doubled then the extension in its length will be O 4 8 cm 0 6 cm 2 54 cm 1 2 cm

10 There is a horizontal film of soap solution On it a thread is placed in the form of a loop The film is pierced inside the loop and the thread becomes a circular loop of radius R If the surface tension of the loop be T then tension in the thread will be a R T c RT b 2RT d TR T

1 A target element A is bombarded with electrons and the wavelengths of the characterstic spectrum are measured A second characteristic spectrum is also obtained because of an impurity in the target The wavelengths of the Ka lines are 196 pm element A and 169 pm impurity If the atomic number of impurity is z 102 1 Find the value of atomic number of element A is 27

Two capillaries of same material but of different radii are dipped in a liquid In one of the capillary the liquid rises to a height of 22 cm and in other to 66 cm The ratio of their radii is Question Type Single Correct Type 1 9 1 2 1 9 3 3 1

Q18 A square prism of wood 50mm x 50mm in cross section and 300 mm long is subjected to a tensile stress of 40 N mm along its longitudinal axis and lateral compressive stress of 20 N mm on one set of lateral face and a lateral tensile stress of 10 N mm on the other set of lateral faces Find the change in dimension of prism Take 0 4 and E 1 5 x 10 N mm 20 N mm 40 N mm 10 N mm 300 mm 20 N mm 10 N mm 50 mm 40 N mm Ans along x 0 88 mm y 0 133 mm z 6 67 x 10 mm

A capillary tube is attached horizontally to a constant head arrangement If the radius of the capillary tube is increased by 10 then the rate of flow of liquid will change nearly by 1 10 2 46 3 10 4 40

ap film is formed on a vertical equilateral triangular frame ABC Side BC can move vertical ining horizontal If m is the mass of rod BC and T is surface tension of soap film Mark th ment s The length of BC in equilibrium is mg 2T mg The length of BC in equilibrium is T Rate The time period of small oscillations about the equilibrium position is The time period of small oscillations about the equilibrium position is

Q12 Determine the total compression of a bar made up of three circular cross sections as shown in figure The diameter being 10mm 20mm and 30mm of the top middle and the bottom portions respectively Take ES 210 GPa EB 105 GPa EC 100 GPa STEEL BRASS COPPER 50 kN 30 mm 20 mm 40 mm

A particle of mass m is moving in y z plane with a uniform velocity v with its trajectory running parallel to ve y axis and intersecting z axis at z a The change in its angular momentum about th origin as it bounces elastically from a wall a y constant is a mva c ymv Z a b 2mva x d 2ymv

86 A uniform rectangular bar of length 7 width b and thickness t is subjected to a tensile stress in longitudinal direction If e be the longitudinal strain developed and u be the Poisson s ratio the resulting volume strain will be A 1 2 C 1 2 B 2 1 D 3 A

Twenty seven droplets of water each of radius 0 1 mm coalesce into a single dro Find the change in surface energy Surface tension of water is 0 072 N m Ans W 1 628 X 10 7 J

A uniform rod of mass M and length L area of cross section A is placed on a smooth horizontal surface Forces acting on the rod are shown in the digram F P Q M L A Y Smooth Surface R PQ QR L 2 In undeformed state Ratio of elongation in section PQ of rod and section QR of rod is A 1 1 B 3 5 C 5 7 2F D 1 2

A steel wire is stretched with a definite load If the Young s modulus of the wire is Y For decreasing the value of y O O Radius is to be decreased Radius is to be increased O Length is to be increased O None of the above